CN111755250B - Capacitor unit - Google Patents

Abstract

The capacitor unit includes: a capacitor (100) having a positive electrode (111) and a negative electrode (112), a positive bus bar (200), a negative bus bar (300), a sealing resin (600), and an insulator (400). The positive and negative bus bars are connected to the positive and negative electrodes, respectively. The sealing resin seals the capacitor, a part of the positive bus bar, and a part of the negative bus bar. The insulator is located between the positive bus bar and the negative bus bar. The insulator includes a recess (411, 411A) recessed from either surface of the insulator facing the positive or negative bus bar. At least a part of the recess is exposed from the sealing resin.

Description

Capacitor unit

Technical Field

The present disclosure in this specification relates to a capacitor unit.

Background

A capacitor unit comprising a plurality of capacitors as one unit is disclosed in WO 2017/204065. The capacitor unit includes a positive bus bar, a negative bus bar, a case, a filling resin (i.e., a sealing resin), and an insulating sheet.

The end of the positive bus bar and the end of the negative bus bar are connected to the positive electrode and the negative electrode of the capacitor, respectively. Different ends of the bus bar (i.e., the external connectors) are connected to an external member located outside the capacitor unit. An insulating sheet is positioned between the positive and negative bus bars to prevent the bus bars from shorting. The housing houses and supports a plurality of capacitors.

The filling resin is filled in the case to seal the capacitor. Specifically, the capacitor connected to the bus bar is housed in the case, and the case is filled with a molten resin. The molten resin becomes solid to become the filled resin.

If the vibration of the connection target member (i.e., the exterior member) propagates to different ends of the bus bar, the stress exerted on the bus bar is concentrated at the boundary between the portion of the bus bar covered with the filling resin and the portion of the bus bar not covered with the filling resin. Therefore, it is necessary to increase the strength of the bus bar to prevent the bus bar from being broken due to such stress concentration.

Incidentally, as the distance between the bus bars is shortened, the inductance is more reduced. This is because the effect of the magnetic fields generated by the currents flowing through the positive and negative bus bars canceling each other is higher.

In contrast, if the distance between the bus bars is shortened, the molten resin is likely to climb up between the bus bars and the insulating sheet due to capillary action. As a result, the boundaries described above are close to the different ends of the bus bar. This increases the amount of displacement of the interface relative to the amount of displacement of the different end portions caused by the vibration. Therefore, the stress concentration at the interface increases, and the bus bar needs to be reinforced.

Disclosure of Invention

An object of the present disclosure is to provide a capacitor unit capable of reducing stress concentration and inductance on a bus bar.

According to a first aspect of the present disclosure, a capacitor unit includes a capacitor having a positive electrode and a negative electrode, a positive bus bar, a negative bus bar, a sealing resin, and an insulator. The positive and negative bus bars are connected to the positive and negative electrodes, respectively. The sealing resin seals the capacitor, a part of the positive bus bar, and a part of the negative bus bar. The insulator is located between the positive bus bar and the negative bus bar. The insulator has a concave portion that is recessed away from either the positive bus bar or the negative bus bar at a portion of the insulator facing the bus bar. At least a part of the recess is exposed from the sealing resin.

According to a second aspect of the present disclosure, a capacitor unit includes a capacitor having a positive electrode and a negative electrode, a positive bus bar, a negative bus bar, a sealing resin, and an insulator. The positive and negative bus bars are connected to the positive and negative electrodes, respectively. The sealing resin seals the capacitor, a part of the positive bus bar, and a part of the negative bus bar. The insulator is located between the positive bus bar and the negative bus bar. Either one of the positive bus bar and the negative bus bar includes a bus bar recess that faces the insulator and is recessed away from the insulator. At least a part of the bus bar concave portion is exposed from the sealing resin.

According to the first aspect, in the concave portion, the distance between the insulator and the bus bar is wider. According to the second aspect, in the bus bar recess, the distance between the insulator and the bus bar is wider. Therefore, the molten resin can be prevented from climbing up between the bus bar and the insulator due to capillary action in the production step of the sealing resin. As a result, the boundary between the portion of the bus bar covered with the sealing resin and the portion of the bus bar exposed from the sealing resin is away from the end portion of the bus bar. The above-mentioned end portion of the bus bar is an end portion which is not connected to the capacitor.

According to the first and second aspects, if vibration from outside the capacitor unit propagates to the end of the bus bar, the amount of displacement of the bus bar at the interface caused by the vibration is reduced, thereby reducing stress concentration at the interface and preventing the bus bar from losing strength.

The parenthetical reference numerals are merely examples showing the correspondence with specific configurations in the embodiments to be described and do not limit the technical features.

Drawings

Fig. 1 is a sectional view of a capacitor unit according to a first embodiment.

Fig. 2 is a perspective view showing the capacitor unit according to the first embodiment without including the case and the sealing resin.

Fig. 3 is an exploded perspective view of the capacitor unit in fig. 2.

Fig. 4 is a perspective view showing a positional relationship of a bus bar and an insulator according to the first embodiment.

Fig. 5 is a perspective view showing a positional relationship of the bus bar and the insulator according to the first embodiment.

Fig. 6 is a sectional view showing a recess formed on an insulating member according to the first embodiment.

Fig. 7 is a perspective view of the insulator itself according to the second embodiment.

Fig. 8 is a sectional view showing a recess formed on an insulating member according to a third embodiment.

Fig. 9 is a cross-sectional view of the insulator itself according to a fourth embodiment.

Fig. 10 is a sectional view showing a bus bar recess formed on a bus bar according to a fifth embodiment.

Detailed Description

Hereinafter, embodiments will be described with reference to the accompanying drawings. Functionally and/or structurally corresponding parts between the embodiments are denoted by the same reference numerals. Hereinafter, the up-down direction of the capacitor unit mounted in the vehicle is referred to as a Z direction, and a direction perpendicular to the Z direction is referred to as an X direction. The direction perpendicular to the Z direction and the X direction is referred to as the Y direction.

(first embodiment)

Hereinafter, the capacitor unit 10 in the present embodiment will be described with reference to fig. 1 to 6. The capacitor unit 10 is applicable to a power converter mounted in a vehicle such as an Electric Vehicle (EV) and a Hybrid Vehicle (HV). Hereinafter, the capacitor unit 10 for a hybrid vehicle will be described. A drive system for an application power converter includes a direct-current power source, a motor generator, and a power converter. The dc power supply is a secondary battery that can be charged and discharged.

The power converter includes a converter, an inverter, a capacitor 100 (see fig. 1), and the like. The converter and the inverter constitute a power conversion portion for converting electric power between the direct-current power supply and the motor generator. Each of the converter and the inverter includes an upper arm circuit and a lower arm circuit, which respectively include switching elements. The switching element may be an Insulated Gate Bipolar Transistor (IGBT).

The capacitor 100 is connected in parallel to the upper arm circuit and the lower arm circuit. The capacitor 100 smoothes the direct current boosted by the converter. The capacitor 100 may be a thin film capacitor. Specifically, the capacitor 100 includes a thin film covering section 110, a positive electrode 111, and a negative electrode 112. The film cover 110 is formed such that a metallized film is wound around the capacitor 100. The metallized film is a dielectric film in which a metal layer is formed on the surface of the dielectric film.

The positive electrode 111 is electrically connected to a metal layer formed on the first surface of the dielectric film. The negative electrode 112 is electrically connected to a metal layer formed on a second surface of the dielectric film opposite to the first surface. The positive electrode 111 is located on a first side of the film cover 110 in an axial direction (i.e., Z-direction) of the film cover 110. The negative electrode 112 is located on a second side of the film cover 110 in the axial direction.

The capacitor unit 10 includes a capacitor 100, a positive bus bar 200, a negative bus bar 300, a sealing resin 600, an insulator 400, and a case 500. Capacitor 100 is accommodated in case 500 in such a manner as to be sealed with sealing resin 600. As shown in fig. 2 and 3, the capacitor unit 10 may include a plurality of capacitors 100. The plurality of capacitors 100 are arranged in a row in a predetermined direction (for example, X direction).

Each of the positive bus bar 200 and the negative bus bar 300 is made of metal having conductivity, and has a plate shape. The positive bus bar 200 includes an electrode connector 211, a bent portion 221, and a straight portion 231. The negative bus bar 300 includes an electrode connector 311, a bent portion 331, and a straight portion 321.

The electrode connectors 211, 311 are connected to the positive electrode 111 and the negative electrode 112, respectively. The total number of the electrode connectors 211 and 311 is the same as the number of the capacitors 100. That is, each of the bus bars 200, 300 includes a plurality of electrode connectors 211, 311.

The bent portions 221, 331 are connected to the upper arm circuit and the lower arm circuit, respectively, and are referred to as external connectors. Specifically, the bent portion 221 of the positive bus bar 200 is connected to a bus bar (not shown) connected to the upper arm circuit by a bolt. The bus bar connected to the circuit corresponds to the external conductor. The bent portion 331 of the negative bus bar 300 is connected to a bus bar (not shown) connected to the lower arm circuit by a bolt. Each bent portion 221, 331 has a bolt hole 222, 332 into which a bolt is inserted.

The number of bent portions 221 of the positive bus bar 200 is the same as the number of upper arm circuits. The number of bent portions 331 of the negative bus bar 300 is the same as the number of lower arm circuits. That is, the bus bars 200, 300 include a plurality of bent portions 221, 331. The plurality of bent portions 221, 331 are arranged at the same position in the Z direction.

The straight portion 231 of the positive bus bar 200 extends straight from the end of the electrode connector 211 to the end of the bent portion 221. Similarly, the straight portion 321 of the negative bus bar 300 extends straight from the end of the electrode connector 311 to the end of the bent portion 331. The straight portions 231, 321 have a plate shape perpendicular to the Y direction and extending along the XZ plane.

The bent portions 221, 331 are bent from the ends of the straight portions 231, 321, respectively. The electrode connectors 211, 311 and the bent portions 221, 331 have a plate shape perpendicular to the Z direction and extending along the XY plane. That is, the straight portion 231, the electrode connector 211, and the bent portion 221 are formed by bending a single plate member. In the same manner, the straight portion 321, the electrode connector 311, and the bent portion 331 may be formed.

The case 500 is made of resin, and accommodates the plurality of capacitors 100. The housing 500 has a rectangular parallelepiped shape including an opening 501. The sealing resin 600 is a resin having an electrical insulating property, and is filled in the case 500. The sealing resin 600 completely seals the plurality of capacitors 100.

The sealing resin 600 also seals a portion of the positive bus bar 200 and a portion of the negative bus bar 300. Specifically, the sealing resin 600 seals the entire electrode connectors 211, 311. The straight portions 231, 321 extend from the inside to the outside of the case 500 through the opening 501, and extend from the inside to the outside of the sealing resin 600. That is, a part of the straight portion 231 and a part of the straight portion 321 are sealed with the sealing resin 600. The bent portions 221, 331 are located outside the sealing resin 600.

The insulating member 400 is made of resin having an electrical insulating property, and has a plate shape. As shown in fig. 4 and 5, the insulating member 400 is located between the positive bus bar 200 and the negative bus bar 300. The insulator 400 includes an insulator body 410 and a support 420. The insulator body 410 has a plate shape perpendicular to the Y direction and extending along the XZ plane. The support 420 has a plate shape perpendicular to the Z direction and extending along the XY plane.

The insulator main body 410 is located between the straight portion 231 of the positive bus bar 200 and the straight portion 321 of the negative bus bar 300. The support 420 faces the bent portion 221 of the positive bus bar 200. The support 420 supports the bent portion 221, thereby preventing the bent portion 221 from being further bent inward with respect to the straight portion 231.

As shown in fig. 6, a space S1 is defined between the straight portion 231 of the positive bus bar 200 and the insulator main body 410. The straight portion 321 of the negative bus bar 300 and the insulator body 410 define a space S2 therebetween. The spaces S1, S2 extend along the entire area of the insulating member 400 in the X direction.

The insulator 400 includes a concave portion 411 on a surface facing the positive bus bar 200, and the concave portion 411 is recessed away from the positive bus bar 200. In detail, the recess 411 is formed on the insulator body 410. The concave portion 411 has a rectangular shape as viewed in the Y direction.

As shown in fig. 3, the insulating member 400 includes a plurality of recesses 411 corresponding to the plurality of bent portions 221. The plurality of concave portions 411 are arranged in a line in the X direction. The center of the concave portion 411 in the X direction is located at the same position as the center of the curved portion 221 in the X direction.

As shown in fig. 4, the width of the concave portion 411 in the X direction is defined as a width L1. The width of the external connector of the busbar 200 facing the recess 411 is defined as a width L2. That is, the width of the curved portion 221 of the positive bus bar 200 in the X direction corresponds to the width L2. The width L1 of the recess 411 is greater than the width L2 of the curved portion 221 of the positive busbar 200.

A part of the recess 411 is filled with the sealing resin 600, and another part of the recess 411 is exposed from the sealing resin 600. A part of the sealing resin 600 located outside the bus bars 200, 300, that is, a part of the sealing resin not located between the bus bars 200, 300 is referred to as an external resin. The left portion of the sealing resin 600 located between the bus bars 200, 300 is referred to as an internal resin. The internal resin is divided into a first resin 610 between the insulator 400 and the positive bus bar 200 and a second resin 620 between the insulator 400 and the negative bus bar 300.

Therefore, the sealing resin filling the portion of the concave portion 411 is the first resin 610. The busbar facing the recess 411 is the positive busbar 200. The positive busbar 200 faces the concave portion 411 such that the concave portion 411 is located on the curved side of the positive busbar 200, and the curved portion 221 extends from the straight portion 231 to the curved side of the positive busbar 200. In other words, the bent portion 211 is bent from the end of the straight portion 231 to a predetermined direction, and the positive bus bar 200 faces the concave portion 411 in the predetermined direction.

The interfaces 611, 621 between the internal resin and the external air are farther from the capacitor 100 in the Z direction than the interface 601 between the external resin and the external air. The interface 601 of the outer resin is located in the housing 500, while the interfaces 611, 621 of the inner resin are located outside the housing 500.

As shown in fig. 6, the interface between the first resin 610 and the outside air is divided into an interface 611 located in the concave portion 411 and an interface 612 located outside the concave portion 411. The interface 611 is closer to the interface 601 of the external resin than the interface 612 in the Z direction. Interfaces 611, 612 between the first resin 610 and the outside air are closer to an interface 601 between the outside resin and the outside air than an interface 621 between the second resin 620 and the outside air in the Z direction (see fig. 3 and 6).

The insulating member 400 includes an edge 412 (see fig. 6) forming the outline of the recess 411, and the edge 412 forms a right angle. Specifically, the edge 412 forms a right angle in a cross section of the insulator 400 taken along the YZ plane shown in fig. 6.

Next, a production method of the capacitor unit 10 will be described. The production method comprises the steps of assembling, bus connecting, encapsulating, curing and the like. These steps are performed by an operator using an injection molding machine, a welding machine, or the like, which injects molten resin.

In the assembling step, the insulator 400 is assembled between the positive bus bar 200 and the negative bus bar 300. In the bus bar connecting step, the electrode connectors 211, 311 of the bus bars 200, 300 are joined to the electrodes 111, 112 of the capacitor 100 by soldering, respectively. In the potting step, the capacitor 100 connected to the bus bars 200, 300 is arranged at a predetermined position in the case 500. A molten resin melted by heat is injected into the case 500. In the curing step, the temperature of the molten resin is further increased to cure the molten resin, thereby forming the sealing resin 600. In the present embodiment, a thermosetting resin is used as the sealing resin 600.

The effect of reducing inductance is increased if the straight portion 231 of the positive busbar 200 and the straight portion 321 of the negative busbar 300 are as close to each other as possible. This is because the effect that the magnetic field generated by the current flowing through the positive bus bar 200 and the magnetic field generated by the current flowing through the negative bus bar 300 cancel each other out is higher.

In contrast, as the positive bus bar 200 comes closer to the negative bus bar 300, the spaces S1, S2 become smaller, and therefore, the later-described molten resin climb-up is likely to occur. That is, in the potting step, a part of the molten resin injected into the case 500 is likely to climb up and pass through the spaces S1, S2 due to capillary action. A part of the molten resin is pulled up between the spaces S1, S2, thereby forming the first resin 610 and the second resin 620.

In the capacitor unit 10 as described above, the insulating member 400 has the concave portion 411 at a position where the insulating member 400 faces the positive bus bar 200. The space S1 in the concave portion 411 is large, so that the molten resin is restricted from climbing upward. That is, the interface 611 of the first resin 610 may be lowered. As shown in fig. 6, the length La of a part of the positive bus bar 200 exposed from the sealing resin 600 in the Z direction is increased.

When the vibration of the bolt propagates to the bent portions 221, 331 of the bus bars 200, 300, the stress received by the bus bars 200, 300 is locally concentrated at a position close to the interfaces 611, 612. The stress concentration position of the bus bar is a boundary position between a portion of the bus bar covered with the sealing resin 600 and a portion of the bus bar exposed from the sealing resin 600. As the length La of the bus bars 200, 300 becomes longer, the displacement amount at the boundary position relative to the displacement amount of the bending portions 221, 331 caused by vibration decreases. As a result, the stress applied to the boundary position is released, and the bus bars 200, 300 are prevented from being damaged around the boundary position.

According to the present embodiment, the concave portion 411 is provided and the length La of the positive bus bar 200 exposed from the sealing resin 600 is made longer, thereby eliminating the stress applied to the positive bus bar 200 near the interface 611. Thus, the positive bus bar 200 is prevented from being damaged around the interface 611.

According to the present embodiment, the concave portion 411 faces the straight portion 231 of the positive busbar 200, thereby preventing the molten resin flowing through the space S1 from reaching the curved portion 221 of the positive busbar 200.

In the present embodiment, the bus bar facing the concave portion 411 is the positive bus bar 200. The positive bus bar 200 includes: a straight portion 231, the straight portion 231 extending straight outward from the interface 601 of the sealing resin 600; and a bent portion 221, the bent portion 221 being bent from an end portion of the straight portion 231 remote from the sealing resin 600. The bus bar having the bent portion is more likely to be damaged due to stress concentration, and thus the stress relaxation as described above is effective.

The stress concentration on the bent side to which the bent portion 221 of the bus bar is bent causes damage on the bus bar more easily than the stress concentration on the side of the bus bar opposite to the bent side. In the present embodiment, the sealing resin 600 is located on the bent side of the positive bus bar 200, and on the opposite side of the negative bus bar 300 from the bent side of the negative bus bar 300. Therefore, the positive bus bar 200 is more susceptible to the shortened length La than the negative bus bar 300, and is easily damaged.

In the present embodiment, the concave portion 411 faces the bus bar that is in contact with the sealing resin 600 on the bus bar bending side. That is, the concave portion 411 is formed on the insulating member 400 at a portion facing the positive bus bar 200, thereby effectively providing a damage prevention effect to the bus bar, which is achieved by lengthening the length La.

The width L1 of the recess 411 is greater than the width L2 of the curved portion 221 of the positive busbar 200 facing the recess 411. Therefore, the recess 411 can of course prevent the resin from climbing up in the X direction of the bent portion 221.

As shown in fig. 6, the edge 412 forming the outline of the recess 411 of the insulating member 400 forms a right angle, which helps prevent the first resin 610 from climbing up due to capillary action at the edge 412. Therefore, the interface 611 of the first resin 610 is prevented from rising, thereby further reducing damage on the positive bus bar 200 due to stress concentration. In fig. 6, the space S1 is less than expected and the first resin 610 is pulled up onto the edge 412.

In the present embodiment, one end portions of the bus bars 200, 300 are connected to the electrodes 111, 112 by bolts, and the opposite end portions of the bus bars 200, 300 are connected to the external conductor. Therefore, the vibration energy applied to the bus bars 200, 300 increases, which may damage the bus bars 200, 300 due to stress concentration. In this case, the capacitor unit effectively utilizes the effect of releasing stress at the interface as described above, thereby preventing damage on the bus bars 200, 300 around the interface.

(second embodiment)

In the first embodiment, the concave portion 411 is kept at a distance from the curved portion 221 in the Z direction (see fig. 3, 4, 6). In the second embodiment, as shown in fig. 7, the concave portion 411 is adjacent to the curved portion 221. In other words, the recess 411 faces the straight portion 231 and the curved portion 221 such that the recess 411 forms a step. The recess 411 is formed in a portion of the insulator main body 410 in the Z direction, not the entire area of the insulator main body 410 in the Z direction.

As shown in fig. 7, the recess 411 has an angular edge 414 on the insulator body 410, and the support 420 has a recess 431, the recess 431 being recessed in the same direction as the recess 411. The support member 420 has another recess 421 recessed in an opposite direction opposite to the recess 431. The support 420 has a rib extending in the Y direction and a plane 430 defined between the rib and the recess 431.

If the molten resin reaches the bent portion 221 above the straight portion 231, the stress concentration is more likely to cause the bus bar to be damaged. Therefore, it is preferable that the molten resin does not reach the bent portion 221. As shown in fig. 6, the molten resin does not reach the curved portion connecting the straight portion 231 and the curved portion 221.

However, if the recess 411 is spaced apart from the bent portion 221 and the space S1 is too narrow, the molten resin may reach the bent portion above the recess 411.

In the present embodiment, the concave portion 411 is close to the curved portion 221, thereby further reducing the possibility that the molten resin reaches the curved portion.

(third embodiment)

In the third embodiment, as shown in fig. 8, the insulating member 400 includes a concave portion 411A facing the negative bus bar 300 in addition to the concave portion 411 facing the positive bus bar 200.

The recess 411 corresponds to a positive recess, and the recess 411A corresponds to a negative recess. The positive busbar 200 corresponds to a busbar facing the recess 411 at the busbar inner surface. The inner surface is the surface on which the generatrix is located when it is bent. The negative busbar 300 is a busbar facing the concave portion 411A at a surface facing the inner surface of the positive busbar 200. The curved portion 221 of the positive busbar 200 is curved from the straight portion 231 in the same direction as the curved portion 331 of the negative busbar 300 curved from the straight portion 321, and the concave portion 411 facing the positive busbar 200 and the concave portion 411A facing the negative busbar 300 are recessed in opposite directions opposite to each other.

The positive recess and the negative recess are formed at different regions of the insulator 400 as viewed in a direction perpendicular to the panel wall of the insulator 400 (i.e., Y direction), respectively. Specifically, the concave portions 411, 411A are formed on different regions of the insulating member 400 in the Z direction (see fig. 8). The recesses 411, 411A are arranged so as not to overlap when viewed in the Y direction.

In fig. 8, the recess 411 is positioned closer to the interface 601 than the recess 411A. The recess 411A may be closer to the interface 601 than the recess 411.

According to the present embodiment, the concave portions 411, 411A are formed on the surfaces of the insulator 400 facing the positive bus bar 200 and the negative bus bar 300, respectively. Therefore, prevention of molten resin from climbing up and lengthening of the length La can be achieved at both the bus bars 200, 300. The stress applied on the interface of both bus bars 200, 300 can be relieved.

The insulating member 400 includes the concave portions 411, 411A, and thus a portion of the insulating member 400 is thinner. The positive recess 411 and the negative recess 411A are formed at different regions of the insulator 400 as viewed in a direction perpendicular to the panel wall of the insulator 400 (i.e., the Y direction). Accordingly, the insulating member 400 can be prevented from being excessively thin. The insulating member 400 maintains strength in the case where the recesses 411, 411A are included on both surfaces.

(fourth embodiment)

In the first embodiment, the edge 412 forming the outline of the recess 411 of the insulating member 400 forms a right angle. In contrast, in the fourth embodiment, the edge 413 forms an acute angle as shown in fig. 9. The edge 413 protrudes toward the busbar (i.e., the positive busbar 200) facing the recess 411. The edge 413 forms an annular shape surrounding the concave portion 411 as viewed in the Y direction. The edge 413 is a burr formed when the insulating member 400 is molded with resin, and the burr serves as the edge 413 without being removed.

The edge 413 protrudes toward the generatrix facing the recess 411, which further prevents the molten resin from climbing up at the edge 413. Thus, the edge 413 may help to lengthen the length La.

(fifth embodiment)

In the embodiment as described above, the insulating member 400 includes the concave portion 411 and/or the concave portion 411A that prevents the molten resin from climbing upward. In the fifth embodiment, as shown in fig. 10, the positive bus bar 200 and the negative bus bar 300 respectively include the bus bar concave portions 230, 330 having the functions as described above. The insulator 400 does not include the recesses 411, 411A.

The bus bar recesses 230, 330 are formed by press molding. Each of the bus bar recesses 230, 330 has a rectangular shape when viewed in the Y direction. The bus bar recesses 230 and 330 are provided corresponding to the plurality of bent portions 221. The plurality of bus bar recesses 230 and 330 are aligned in a row in the X direction. The center portions of the busbar recesses 230, 330 in the X direction correspond to the center portions of the bent portions 221 in the X direction. A center portion in the X direction of busbar recess 230 of positive busbar 200 corresponds to a center portion in the X direction of busbar recess 330 of negative busbar 300. The width of the busbar recess 230, 330 is larger than the width of the bent portion 221, 331 of the busbar 200, 300 in the X direction.

The sealing resin 600 is filled in a part of the bus bar recess portions 230, 330, and the other part of the bus bar recess portions 230, 330 is exposed from the sealing resin 600. Interface 611 of first resin 610 located in bus bar recess 230 is closer to interface 601 of the external resin than interface 612 of first resin 610 located outside bus bar recess 230 in the Z direction. Interface 621 of second resin 620 located in bus bar recess 330 is closer to interface 601 of the external resin than interface 622 of second resin 620 located outside bus bar recess 330 in the Z direction. The interfaces 611 and 612 of the first resin 610 and the interfaces 621 and 622 of the second resin 620 are located at the same position in the Z direction.

As a result, in the fifth embodiment, it is possible to prevent both the bus bars 200 and 300 from climbing up and to increase the length La. The stress applied at the interface of both bus bars 200, 300 can be relieved.

(other embodiments)

The disclosure of the present specification is not limited to the embodiments described above. The present disclosure includes the embodiments described above and variations based on these embodiments by those skilled in the art. For example, the present disclosure is not limited to the combination of elements disclosed in the embodiments. The present disclosure may be implemented in various combinations. The technical features disclosed in the specification are shown in the claims, and it should be understood that the present disclosure includes various modifications within the scope of the claims and their equivalents.

In the embodiment as described above, the bus bar 200, 300 includes the straight portion 231, 321 and the bent portion 221, 331, but the bus bar 200, 300 may not include the bent portion 221, 331. The bus bars 200, 300 may have a straight shape.

In the first embodiment, the bus bar facing the concave portion 411 is a bus bar in which the inner surface of the bus bar faces the concave portion 411, that is, the positive bus bar 200. However, the bus bar facing the concave portion may be a negative bus bar 300, the negative bus bar 300 facing the concave portion from a side opposite to the bent side of the negative bus bar 300.

In the first embodiment, the width L1 of the recess 411 is larger than the width L2 of the curved portion 221 of the positive busbar 200. However, the width L1 of the recess 411 may be equal to or shorter than the width L2 of the bent portion 221.

In the third embodiment, the two concave portions are arranged so as not to overlap with each other when viewed in the Y direction, but the two concave portions may be arranged so as to partially overlap when viewed in the Y direction.

In the above embodiment, the capacitor 100 of the capacitor unit 10 is a smoothing capacitor to smooth the direct current boosted by the converter circuit. However, the capacitor 100 may be a filter capacitor configured to remove noise.

In the above embodiment, the capacitor unit 10 may be attached to a motor mounted in a vehicle. In this case, the housing 500 of the capacitor unit 10 is fixed to the housing of the motor by bolts or welding. The case 500 of the capacitor unit 10 may be integrally molded with the case of the motor using metal.

In the first embodiment, both the bus bars 200, 300 are fixed to the outer conductor with bolts, but both the bus bars 200, 300 may be fixed to the outer conductor by welding.

Claims (11)

1. A capacitor unit, comprising:

a capacitor (100) having a positive electrode (111) and a negative electrode (112);

a positive bus (200) connected to the positive electrode;

a negative busbar (300) connected to the negative electrode;

a sealing resin (600) that seals the capacitor, a portion of the positive bus bar, and a portion of the negative bus bar; and

an insulator (400) between the positive bus bar and the negative bus bar, wherein

The insulator includes a concave portion (411, 411A) recessed from either surface of the insulator facing the positive bus bar or the negative bus bar,

at least a part of the recess is exposed from the sealing resin.

2. The capacitor cell of claim 1,

the bus bar facing the recess includes:

a straight portion (231) extending straight outward from an interface of the sealing resin; and

a curved portion (221) that is curved from an end portion of the straight portion that is away from the sealing resin,

the concave portion faces the straight portion.

3. The capacitor cell of claim 2,

the curved portion is curved in a predetermined direction from an end of the straight portion, and

the bus bar faces the recess in the predetermined direction.

4. The capacitor unit of claim 2 or 3,

the recess is located near the bend.

5. The capacitor unit of any one of claims 1 to 3,

the recess has a width (L1) greater than a width (L2) of a busbar facing the recess.

6. The capacitor unit of any one of claims 1 to 3,

the insulator includes edges (412, 413) that outline the recess, and the edges form a right angle or an acute angle.

7. The capacitor cell of claim 6,

the edge protrudes towards a busbar facing the recess.

8. The capacitor unit of any one of claims 1 to 3,

the recess is one of a plurality of recesses, and

the plurality of recesses are formed on a first surface of the insulating member facing the positive bus bar and a second surface of the insulating member facing the negative bus bar.

9. The capacitor cell of claim 8,

when the recess formed on the first surface of the insulator is referred to as a positive recess (411) and the recess formed on the second surface of the insulator is referred to as a negative recess (411A),

the insulating member is plate-shaped, and

the positive recess is formed in a region different from the negative recess when viewed from a direction orthogonal to the plate surface of the insulating member.

10. The capacitor unit of any one of claims 1 to 3,

an end of the positive bus bar remote from the positive electrode and an end of the negative bus bar remote from the negative electrode are fixed to an external conductor by bolts or welding.

11. A capacitor unit, comprising:

a capacitor (100) having a positive electrode (111) and a negative electrode (112);

a positive bus (200) connected to the positive electrode;

a negative busbar (300) connected to the negative electrode;

a sealing resin (600) that seals the capacitor, a portion of the positive bus bar, and a portion of the negative bus bar; and

an insulator (400) between the positive bus bar and the negative bus bar, wherein

At least one of the positive bus bar and the negative bus bar includes a bus bar recess (230, 330) facing the insulator and recessed away from the insulator, and

at least a part of the bus bar recess is exposed from the sealing resin.

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